interface State {
    void onTemperatureBelow20AndHasWater(WaterTank tank);
    void onTemperatureReached100(WaterTank tank);
    void onNoWater(WaterTank tank);
    void onBurnedOut(WaterTank tank);
    void onMorning7(WaterTank tank);
    void onNight11(WaterTank tank);
}